This invention relates to a method of preparing alkane diamines. In particular, it relates to a novel method for preparing the diamines from vicinal nitroketones.
Diamines, such as ethylene diamine, propylene diamine, etc., have long been known and are useful in preparing textile finishing resins, fungicides, herbicides, corrosion inhibitors, petroleum additives and polyamides to name but a few. The diamines can be prepared by, for example, treating ethylene dichloride with ammonia and a mixture of products is generally obtained albeit that reaction conditions can vary. For example, at low temperatures and pressures ethylene diamine is predominantly formed in low yield. When elevated temperatures and pressures are employed, the yield of ethylene diamine is higher, but the amount of polyethylene polyamines formed is likewise greater.
Diamines may also be prepared by reacting a primary or secondary amine and formaldehyde with a nitroparaffin to form a nitroamino intermediate and thereafter hydrogenating the intermediate. Alternately, a nitroolefin and a primary amine may be reacted to form a similar nitroamino intermediate followed by hydrogenating the intermediate. The aforementioned methods are unsuitable for preparing 1,2-diamines inasmuch as each of the nitroamino intermediates are unstable and undergo further reaction or decomposition.
Another method for preparing 1,2-diamines may be by the action of a nitrogen oxide, such as N.sub.2 O.sub.3 or N.sub.2 O.sub.4, on olefins at low temperature followed by reduction of the intermediate dinitrocompound. However, the nitration of olefins with nitrogen oxides leads to the formation of complex mixtures including nitronitroso, nitronitrate, nitronitrile, nitroalochol, nitroolefin and dinitrocompounds as well as products of olefin oxidation. Only a fraction of the olefin charged can be converted to dinitro or nitronitroso derivatives and thence to the diamine.
It is therefore an object of this invention to provide a method for the preparation of alkane diamines.
Another object of this invention is to provide a method for the preparation of alkane diamines in high yields.
Yet another object of this invention is to provide a method for the preparation of alkane diamines in the absence of substantial by-product formation.
A further object of this invention is to provide a method for preparing diamines from stable intermediate products.
Other objects and advantages will become apparent from a reading of the following detailed description and examples.